Effects of horse and fetal calf serum on the expression of tumor-associated antigen and tumorigenicity of L5178Y leukemia/lymphoma cells.

This study investigates the impact of horse serum and fetal calf serum on the expression of a tumor-associated antigen and its potential link to the tumorigenicity of a particular type of leukemia/lymphoma cells, the L5178Y. The research reveals that the antigen, stored within both non-solubilized and solubilized membrane extracts, is only identifiable in cells grown in horse serum and appears to have a role in the ability of these cells to cause tumors.

Identification of Tumor Antigen

• This research identified a tumor antigen (TA) associated with murine leukemia-lymphoma L5178Y cells using ELISA and IIF techniques. ELISA is a test that involves the detection and measurement of immune responses in the form of antibody or antigen concentrations, while indirect immunofluorescence is a method used to visualize the localization of specific proteins or antigens in cells.
• The identified antigen was present in both non-solubilized and 0.5% NP-40 solubilized membrane extracts.
• The study used rabbit anti-L5178Y lymphoma serum, a substance that had been absorbed with normal mouse tissues, to identify the TA in extracts of L5178Y lymphoma and L5178Y leukemia cells grown in horse serum (L5178Y/HS), but not in L5178Y cells grown in fetal calf serum (L5178Y/FCS).

Expression of Antigen and Tumorigenicity

• Through membrane IIF, it was showed that the antigenic activity in lymphoma and L5178Y/HS cells was significantly higher (73-88%), while L5178Y/FCS cells showed no reactivity. These suggest that the presence of the antigen was linked to the in-vivo tumorigenicity of the L5178Y cells.
• Another experiment involved the use of goat anti-AKR virus serum, which showed reactivity with lymphoma and both types of L5178Y/HS and L5178Y/FCS cells, but it did not block the reactivity of RALS to lymphoma.

Characteristics of Tumor Antigen

• The antigenic activity of the lymphoma extract was diminished by heat exposure, trypsin digestion, and extreme pH conditions, suggesting instability under these conditions.
• The antigen was purified and further characterized as a glycoprotein with a molecular weight of approximately 64,000 daltons using SDS-PAGE analysis. SDS-PAGE is a technique widely used in biochemistry, genetics, and molecular biology to analyze the mass and purity of proteins.